Tabular silver halide grains are well-known for practical use since the early eighties: if present in one or more light-sensitive hydrophilic layers of a silver halide photographic material a high covering power can be expected, even for forehardened silver halide photographic materials as e.g. disclosed in U.S. Pat. No. 3,414,304.
As rapid processing in ecologically justified circumstances is becoming more and more desirable materials having hydrophilic layers containing tabular grains in processing solutions free from hardening agents as have e.g. been proposed in U.S. Pat. No. 5,318,881. With respect to rapid processing ability tabular grains rich in silver chloride are more preferred than tabular grains rich in silver bromide. As has been shown in EP-A 0 678 772 tabular grains rich in silver chloride can provide a high sensitivity in silver halide photographic materials coated from such emulsions. Even in a total processing time of up to 50 seconds with low regeneration amounts of hardener-free processing solutions suitable images are obtained without leaving dye stain, generated from huge amounts of spectral sensitizer. Moreover a suitable black image tone is attained.
In the processing of silver halide photographic materials having tabular grains rich in silver bromide the presence in the developer and in the developer replenisher of bromide ions as a developer restrainer leads to an optimised relationship between fog level, speed and covering power. However in the processing of silver halide photographic materials having tabular grains rich in silver chloride, bromide ions in the developer act as a developer restrainer too, leading to an optimized relationship between fog level and speed, but to an insufficient covering power, wherein said covering power is expressed as density per gram of developed silver. Although covering power is higher in the absence of bromide ions, an increased fog level simultaneously appears which is disadvantageous with respect to sensitometric characteristics and image quality of the processed material.
Loss of the said advantages is not appreciated as higher coating amounts of silver are required in order to get the same maximum density. Such measure is clearly disadvantageous with respect to ecology (more chemical waste after processing) and rapid processing (longer processing times), especially in radiographic applications where high speed, high image quality, rapid processing and ecology become ever more important for the customer.